js截取路径参数

(function ($) {
    $.getUrlParam = function (name) {
        var reg = new RegExp("(^|&)" + name + "=([^&]*)(&|$)");
        var r = window.location.search.substr(1).match(reg);
        if (r != null) return unescape(r[2]); 
      return null;
    };
})(jQuery);

var userId  = $.getUrlParam('userId');

//设备上物理像素和设备独立像素(device-independent pixels (dips))的比例

var device = window.devicePixelRatio;

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